1. Field of the Invention
The invention relates to the hydrogenation of unsaturated terpenes and more particularly relates to the selective hydrogenation of .alpha.-pinene to obtain cis-pinane.
2. Brief Description of the Prior Art
Representative of the prior art is the disclosure found in U.S. Pat. No. 4,018,842. This patent discloses the selective hydrogenation of .alpha.-pinene to obtain cis-pinane, employing as the hydrogenation catalyst a partially poisoned nickel catalyst. Although good selectivity of hydrogenation is achieved by the prior art process, the catalyst preparation is not without problems and frequent replacement of spent catalyst is required for subsequent hydrogenations. Furthermore, the most selective hydrogenations required impractically long times (up to 64 hours) for complete reaction.
By the method of my invention, a simple, commercially available compound or composition may be employed as the catalyst and the used catalyst re-used a plurality of times without further treatment or rejuvenation, particularly in the absence of catalyst poisons.